The above-referenced patent applications disclose aircraft using a free wing configuration. As used in this present specification, a free wing or "freewing" is a wing attached to an aircraft fuselage in a manner such that the wing is freely pivotable about its spanwise axis. This arrangement enables the wing to have an angle of attack which is determined solely by aerodynamic forces acting on the wing. Rotation of the wing, without pilot intervention, induced by changes in the direction of relative wind over the wing surfaces, causes the angle of incidence between the wing and the aircraft fuselage to vary so that the wing presents a substantially constant angle of attack to the relative wind which, in horizontal flight, enables the aircraft to be essentially stall free.
The free wing is free to rotate or pivot about its spanwise axis. The free wing generally includes left and right wings extending from opposite sides of the fuselage; these wings are coupled together to collectively freely pivot about the spanwise axis. The left and right wings may be adjustable in pitch relative to one another as disclosed in the aforesaid applications, the relevant disclosures of which are incorporated by reference herein. The aircraft may further include rudders and elevators in the tail section which may be controlled in a conventional manner for yaw and pitch control, respectively. Further, it will be appreciated that other types of propulsion systems may be utilized, such as variable-pitch propellers, as disclosed in co-pending application serial no. To Be Assigned, entitled "STOL/VTOL Free wing Aircraft with Variable Pitch Propulsion Means", filed concurrently herewith, counter-rotating propellers and multi-engine arrangements attached to the fuselage.
Because one of the major advantages of a free wing aircraft is the intrinsic stability of the aircraft, the aircraft is particularly suitable for use as an unmanned aerial vehicle (UAV) where a highly stable platform is necessary and desirable. For example, UAV's are often used by the military as platforms for maintaining sensors trained on a target. Fixed wing UAV aircraft have a high sensitivity to turbulence, particularly at low altitudes, thus a stabilization system is required for onboard sensors to counter turbulence-induced platform motion. The high stability of a free wing aircraft eliminates or minimizes the stabilization problem in a UAV aircraft because the platform itself, i.e., the fuselage, is much more stable even in low-altitude, highly turbulent conditions.
One disadvantage of any aircraft, and particularly, prior art UAV aircraft, is that, in the event a component of the aircraft is damaged, the entire aircraft is downed until the component can be repaired.
Accordingly, it is an object of the present invention to provide an improved free wing aircraft minimizing the "down time" of the aircraft due to damage to one or more components.
Another object of the invention is to provide an aircraft an improved free wing aircraft permitting easy replacement of damaged components.
Yet another object of the invention is to provide an improved free wing aircraft including a means for quickly removing and installing components, particularly, wings and tail booms, to the fuselage.